CVE-2026-55637

Estado: AplazadaAlta (8.8)—

genieacs-mcp is an MCP server for GenieACS written in Go. Prior to 0.3.2, the Streamable HTTP transport in cmd/server/main.go creates an unauthenticated /mcp listener on the default MCP_LISTEN_ADDR value 127.0.0.1:8080 when MCP_AUTH_TOKEN is unset and the httpSrv.Start(addr) branch does not validate the Host or Origin headers. A malicious website can use DNS rebinding to send browser requests with attacker-controlled Host and Origin values to the loopback listener, initialize an MCP session, list tools, and invoke operations against the GenieACS NBI configured by ACS_URL.

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Successful exploitation can expose or modify CPE management state, including device reboots, firmware tasks, TR-069 parameter changes, presets, provisions, tags, connection requests, and task operations. The npm wrapper is not affected because it forces TRANSPORT=stdio and does not expose an HTTP listener. This issue is fixed in version 0.3.2.

CVSS

Versión: 4.0
Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:H/VI:H/VA:N/SC:H/SI:H/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Puntuación base: 8.8

Probabilidad de explotación (EPSS)

Probabilidad de explotación en los próximos 30 días: 0.26%
Percentil entre todas las CVEs puntuadas: 17
Fecha de la puntuación: 5/10/2026

EPSS (Exploit Prediction Scoring System, de FIRST) estima la probabilidad de que una vulnerabilidad sea explotada en 30 días. Complementa a CVSS (impacto) y a CISA KEV (explotación confirmada).

🎯 Técnicas ATT&CK

Cómo se explota esta vulnerabilidad y qué consigue el atacante, en el lenguaje de MITRE ATT&CK.

ExplotaciónT1189 Drive-by Compromiseinitial access85 %
Impacto principalT1565.001 Stored Data Manipulationimpact75 %
Impacto secundarioT1005 Data from Local Systemcollection65 %
Impacto secundarioT1499.004 Application or System Exploitationimpact70 %

DNS rebinding vía navegador (XSS-like) contra listener HTTP no autenticado en loopback. Modificación/exposición de estado de gestión de CPE (T1565.001), potencial DoS por reboot (T1499.004), lectura de configuración (T1005).

Inferido por nuestro agente de análisis a partir de la descripción oficial, el vector CVSS y la CWE, y comprobado por un supervisor. Puede contener errores.

🛡️ Mitigaciones ATT&CK que cubren estas técnicas

User Training Restrict Web-Based Content Restrict File and Directory Permissions Remote Data Storage Filter Network Traffic Encrypt Sensitive Information

Tecnologías afectadas (1)

⚠ Inferidas por IA a partir de la descripción — NVD aún no ha analizado esta CVE; no son CPE verificados.

Genieacs — Genieacs-mcp^AI

CWE

CWE-346

Referencias

JSON original (NVD)

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  "id": "CVE-2026-55637",
  "cveTags": [],
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        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
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  "published": "2026-08-25T18:17:56.157",
  "references": [
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      "url": "https://github.com/GeiserX/genieacs-mcp/commit/577306d78190622eee97e362b042a69499ef373f",
      "source": "security-advisories@github.com"
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          "value": "CWE-346"
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    {
      "lang": "en",
      "value": "genieacs-mcp is an MCP server for GenieACS written in Go. Prior to 0.3.2, the Streamable HTTP transport in cmd/server/main.go creates an unauthenticated /mcp listener on the default MCP_LISTEN_ADDR value 127.0.0.1:8080 when MCP_AUTH_TOKEN is unset and the httpSrv.Start(addr) branch does not validate the Host or Origin headers. A malicious website can use DNS rebinding to send browser requests with attacker-controlled Host and Origin values to the loopback listener, initialize an MCP session, list tools, and invoke operations against the GenieACS NBI configured by ACS_URL. Successful exploitation can expose or modify CPE management state, including device reboots, firmware tasks, TR-069 parameter changes, presets, provisions, tags, connection requests, and task operations. The npm wrapper is not affected because it forces TRANSPORT=stdio and does not expose an HTTP listener. This issue is fixed in version 0.3.2."
    }
  ],
  "lastModified": "2026-09-09T21:07:31.353",
  "sourceIdentifier": "security-advisories@github.com"
}